1. The field of art to which the invention pertains includes the art of measuring and testing as directed to fluid pressure gauges.
2. Gauge instruments and particularly pressure gauges or the like have been widely used and are commercially available from a variety of manufacturing sources. Being that such pressure gauges enjoy very extensive commercial and industrial use, they are supplied by a plurality of manufacturers and are regarded as high production items. Because they are sold in very price conscious competition, each manufacturer instinctively strives to reduce product costs by improvements, however marginal, which reduce labor and/or materials that can contribute to cost savings in the end product.
A common form of case construction for a pressure gauge comprises the "solid front" type in which an intermediate wall separates the case into front and rear compartments. In the usual arrangement, the front compartment contains the indicating mechanism, whereas the pressurized element is contained in the rear compartment such that should the element incur failure from overpressure or whatever, relief is afforded rearward rather than forward of the case. Construction of the solid front gauge case is largely governed by the American National Standard Institute (ANSI) Standard B40.1-1974, Section 3.1.1.2.
Typical prior art solid front gauge case constructions as shown by the patent literature include those in which the solid front wall is separately fabricated and then joined to the peripheral case wall of another construction as, for example, disclosed in U.S. Pat. Nos. 4,154,166 and 4,175,444. There are also those in which the solid front wall is cast or molded integral with the peripheral wall as disclosed, for example, in U.S. Pat. Nos. 2,215,013 and 2,752,787. Whereas it has long been recognized that the aforementioned solid front gauge constructions have been comparatively costly to manufacture, it has not heretofore been known how to significantly reduce such costs.